Synthetic Transmission Oil

[montmil]

One thing, of many, that I like about these old Beemers is the feel of the bike. You get so many mechanical inputs it's quite the sensory event. Even shifting gears is pretty cool. Justin's shift linkage is elegant. That and a new shift lever bearing have made a vast improvement in stirring the gear box... without too many errors on my part.

Today, I warmed up the lubes with a short ride then drained the transmission. Refilled with Mobil 1 synthetic gear oil and, whoa!, even slicker shifting. Think I'll keep it for awhile.

Also, while lying beside the bike watching the oil drain into a coffee can -it's been a very bus day- I wiped off the trans drain plug and thought to myself, "Self, that looks just like the drain plug in the '86 Cabriolet." Had a used drain plug for comparison. Screwed it in and, yep, it's a match. Except no magnetic steel particle catcher. Next, I compared the copper washers for the Cabrio's drain plug and they are also the BMW required size. Since the R65s washer was looking like a flattened Miller can, I used a new VW copper washer for reinstall.

Energized by all this fun, I logged onto my Phoenix AZ-based VW supplier https://www.autohausaz.com and got part numbers and prices:

Oil Drain Plug  14x11x1.5 with a 19mm bolt head (same as the R65)
N90288901 Febi-Bilstein
VW lists at $2.25, Max BMW at $9.39  [smiley=furious3.gif] or you can get it at AutoHausAZ for $0.98

Copper 14mm Oil Drain Plug Gasket  14x20x1.5mm
007630-014106
VW lists at $0.70, Max BMW at $0.50 or you can get it at AutohausAZ for $0.13
     (I buy these gasket washers by the bag as the Cabriolet's manual "suggests" a new one at each oil change. That's every 90 days for me.)

Here's the direct link to the "washers, aluminum and copper" page
https://www.autohausaz.com/search/product.aspx?sid=duovpx55snjo0o451xec0h21&makeid=800026@VW&modelid=1280348@CABRIOLET%20%20&year=1986&cid=99@Tools%20%26%20Shop%20Supplies&gid=1111@Miscellaneous%20Nuts,%20Bolts,%20Washers

Anyway, Y'all have fun out there

[Justin B.]

That's cool, I think the copper washers are superior to the aluminum cheapies...  Did you go back with 75w90 or the 80w140 Mobil 1?  I found the thicker stuff allowed just a tad better shifting when up to temperature.  The only bad thing is all of the places I've found the 80w140 at charge twice as much as the 75w90!!  I did find ONE quart of Royal Purple 80w140 at Pep Boys for the same price as the thin stuff but they only had one quart of it...

[Bob_Roller]

Thanks for the link to autohaus, at least for me , it's local, they beat the local dealers prices for BMW cage parts.

Keep posting updates on the synthetic gear oil for the transmission, I was going to change to full synthetic after I had my transmission rebuilt about 15 months ago, but I had a real bad experience with Mobil 1 synthetic motorcycle oil, leaked out of the rear main seal after about 5 months of use.

I think synthetics are the way to go, ( I've used Mobil 1 in my cages since 1981) but I've heard a lot of reports of leakage in older bikes.

I've wanted to get a magnetic drain plug for the engine, is the transmission drainplug the same size and thread of the oil drainplug ?

[montmil]

...Did you go back with 75w90 or the 80w140 Mobil 1?  I found the thicker stuff allowed just a tad better shifting when up to temperature.

75w90 at AutoZone. Looked at the 80w140 but... ya know I just didn't know. I may give it a shot. I've thrown so much cash at this scooter, what's another fifteen bucks?

[montmil]

I've wanted to get a magnetic drain plug for the engine, is the transmission drainplug the same size and thread of the oil drainplug ?

Dunno, Bob. Just got a new filter and metal seal and big rubber o-ring. I'll try to remember to update your question. Thought you'd be hooked up with Autohaus. I like their whole operation.

[Semper Gumby]

I've been using the Valvolene Sythetic Blend (Blue bottle) 80W90 in the winter and 85W140 in the summer in the Final drive, Drive shaft and Tranny.  This means I change it out twice a year and catch problems (water=baaad) quickly.  I used the BMW 75W140 synthetic once and it felt like water (which I don't like in my bike) and it leaked out the shifter shaft one night a left a nice 1 foot wide puddle of clean expensive oil on the floor of my shop.  At least with the Valvolene it seeps first before a leak becomes a big problem...  

TTFN,

[montmil]

I've been using the Valvolene Sythetic Blend (Blue bottle) 80W90...

I looked at the Valvoline "blue bottle" and believe the label said it was a blend of both synthetic and dino oils. This could be a good thing.

So, Bill, do you notice a difference in ease of shifting, noise, etc?